Bow hunter’s stroke due to instability at the uncovertebral C3/4 joint

Abstract

Bow hunter's stroke is typically due to mechanical compression or stretching of the dominant vertebral artery (VA) during contralateral head rotation against the bony elements of the atlas and axis. We report a case of vertebrobasilar insufficiency due to bilateral vertebral artery occlusion at the left C3-4 and the right C1-2 junction on rightward head rotation. A 64-year-old man experienced ischemic symptoms during 90°head rotation to the right with complete resolution of symptoms after returning his head to the neutral position. Dynamic cervical angiography with rightward head rotation showed severe compression of the right VA at the transverse foramen of C3-4 and mechanical stenosis of the left VA at the C1-2 level. During head rotation, the flow of the right VA was decreased more than the left side. Cervical 3-D computed tomography (CT) on rightward head rotation demonstrated displacement of the uncovertebral C3-4 joint, with excessive rotation of the C3 vertebral body. Based on these findings, instability at C3-4 was suspected to be the main cause of the vertebrobasilar insufficiency. Anterior discectomy and fusion at the C3/4 level were performed. Postoperatively, the patient experienced complete resolution of symptoms, and dynamic cervical angiography showed disappearance of the compression of the right VA. To our knowledge, this is the first reported case of bow hunter's stroke diagnosed by dynamic cerebral angiography and cervical 3-D CT without angiography, and treated by anterior decompression and fusion without decompression of the VA.

Fusion Surgery for Recurrent Cerebellar Infarctions Due to Bilateral Atlantoaxial Rotational Vertebral Artery Occlusion

“…A literature review identifi ed 7 cases of bilateral RVAO. [5][6][7][8][9][10][11] In all of these cases, with the exception of 1 unspecifi ed case, either RVAOs or RVAO was involved at the subaxial level, consisting of mixed-type BHS ( Table 1 ). …”

Advances in the Pathogenesis, Diagnosis and Treatment of Bow Hunter's Syndrome: A Comprehensive Review of the Literature

“…Other patients may have received conservative treatment at the beginning, and then, had to change to surgical treatments like decompression or fusion when the symptoms had not improved [14,51]. Also, there was a case who applied for coil embolization of his right VA because of a focal dissection after a 3-month conservative therapy with no improvement of his symptoms [20].…”

“…In prior reports, many patients underwent decompression through an anterior or posterior approach according to the site of compression [15,17,19,21,30,33,40,41,51,52,53]. In another 2 cases, 1 patient finally received anterior intervertebral fusion because of uncovertebral joint instability [14], and the other posterior fixation and fusion because of facet hypertrophy [29]. Both of these two methods can immediately relieve the symptoms.…”

“…The former is often caused by disc herniation [2,4], abnormal bony structures (e.g. osteophyte [7,8,9], idiopathic skeletal hyperostosis [10] and spondylotic changes [11]), ligament [4], neck muscle hypertrophy [12], VA dissection [13] and some other causes like an instability of the uncovertebral joint [14]. Osteophytes, or bone spurs, are the most common etiology of BHS [3].…”

Rotational vertebral artery occlusion secondary to adjacent-level degeneration following anterior cervical discectomy and fusion

“…3,9,15,17,18,22,37 The majority of these cases were secondary to spondylotic changes. Here, we report a case of RVAO caused by nondominant VA compression at a vertebral segment adjacent to a previously performed anterior cervical discectomy and fusion (ACDF).…”